.pulse {
    animation-name: pulse;
    animation-duration: 1s;
    animation-iteration-count: infinite;
}
/* css 性能优化 GPU加速 动画不要影响周围的文档流*/
@keyframes pulse {
    from {
        transform: scale3d(1, 1, 1);
    }
    50% {
        transform: scale3d(1.5, 1.5, 1.5);
    }
    to {
        transform: scale3d(1, 1, 1);
    }
}